A typical flashlight has a casing extending along an axis, a light source, and a front-end lens mounted on a lamp head. The lamp head can be axially shifted relative to the light source.
More particularly as described in U.S. Pat. No. 7,040,775 such a flashlight has a convergent lens mounted at the front end, a light source, and a partially light-transparent image carrier is between the convergent lens and the light source. In order to adjust the image, the image carrier is mounted on a longitudinally or axially displaceable sliding sleeve whose longitudinal or axial displacement changes both the spacing of the light source from the convergent lens as well as the spacing of the image carrier from the convergent lens. Aside from the lamp head and the casing, at least three additional attachment elements are provided for the displaceable mounting of the image carrier—specifically, an adapter, a guide sleeve, and a sliding sleeve—with the result that manufacturing the flashlight, in particular, is relatively costly.
In addition, flashlights are well known in which, in order to focus the emitted light, the lamp head and reflector mounted therein and the casing including a light source are connected to each other by screwthreads in such a way that the reflector and the light source can be displaced relative to each other by relative rotation. This design has the disadvantage, however, that two hands are always required for focusing, the casing being held tight by one hand while the lamp head is rotated with the other hand, or vice versa.